Final answer:
A benchmark provides elevation data relative to sea level, which a monument does not. Benchmarks are used for accurate geodetic data, while monuments are markers of cultural or historical significance.
Step-by-step explanation:
Benchmarks and monuments are both used for surveying and marking important locations on the earth's surface. However, a benchmark specifically provides elevation data relative to sea level, which a monument does not. Benchmarks are created and maintained by surveyors to mark precise elevation points, and this information is essential for a variety of applications including mapping, construction, and environmental monitoring.
Monuments, on the other hand, often serve as historical or commemorative markers and do not necessarily provide any standardized scientific data like elevation. While monuments may have a coordinate location associated with them, they are typically not used as reference points for elevation.
Therefore, the key difference between a benchmark and a monument is that a benchmark provides accurate geodetic data, particularly elevation, while a monument is generally a marker of cultural or historical significance without any specific geodetic information unless it has been repurposed as a survey marker.